Agricultural feed bagging machines have been employed for several years to fill, pack, or bag silage or the like into elongated plastic bags. In these bagging machines, silage or the like is supplied to the forward or intake end of the bagging machine and is fed to a rotor that conveys the silage into a tunnel on which the bag is positioned so that the bag is filled. As silage is loaded into the bag, the bagging machine moves away from the filled end of the bag in a controlled fashion so as to achieve uniform compaction of the silage material within the bag. In early bagging machines, a backstop structure yieldably engaged the closed end of the agricultural bag to resist the movement of the bagging machine away from the filled end of the agricultural bag as silage is forced into the bag. These machines included a pair of drums rotatably mounted on the bagging machine with a brake associated therewith for braking or resisting the rotation of the drum with a selected brake force. A cable is wrapped around the drum and is connected to the backstop.
In more recent bagging machines, a density control means, which included a plurality of cables, was positioned in the flow of the silage material being bagged. In order to vary the density of the material in the machine, more or less cables would be employed based on the material being packed. For example, corn silage flows easily and would require more cables while alfalfa packs hard and would use less cables. Other arrangements are known in which the density of the material in the bag is controlled by a density control means positioned in the path of the material being bagged.